On August 19, 1947, Dutch chemists David Adriaan van Dorp and Josef Ferdinand Arens synthesized vitamin A or retinol for the first time in history. The same year Otto Isler introduced the vitamin into production.
The ancient Egyptians cured blindness with compresses made of chicken liver juice. In ancient Greece, skin diseases were treated with liver compresses and by eating liver. During World War I, it was discovered that such an eye pathology as xerophthalmia can develop from a lack of butter in the diet. All these creepy stories are connected to the lack of vitamin A or retinol.
Retinol is a form of vitamin A that includes the retinoid and carotenoid compounds. The latter are the precursors of vitamin A. The most famous of them is β-carotene. The body needs this vitamin to regulate protein synthesis, normal metabolism, bone and teeth formation, and growth of new cells. It is called the “elixir of youth” and is added to anti-wrinkle creams and anti-acne medications. However, a high dose of retinol is harmful to the human body, and it should be used with great care. Retinol creams and medications should only be used under medical advice.
The vitamin was not discovered immediately and synthesized even later. In 1913, two groups of researchers conducted essentially similar experiments without prior agreement. Elmer McCollum and Marguerite Davis of the University of Wisconsin and Thomas Osborne and Lafayette Mendel of the Yale University experimented on laboratory mice, dividing them into two groups based on the type of their diet.
The animals that were fed pure casein, fat, lactose, starch, and salt did not feel well and died within two months. Those mice that had butter, cod liver oil and eggs added to their diet felt fine. Scientists realized that besides fats, proteins and carbohydrates, the living body needed something else. Some mysterious substance that was present in the food.
Elmer McCollum went even further and divided the new compounds into two classes – “fat-soluble factor A” (containing vitamins A, E, and D) and “water-soluble factor B.” In 1920, Jack Cecil Drummond renamed vitamins according to the symbols of the Latin alphabet; the vitamin found by the scientists was classified as “A,” because it was discovered first. The same year, Frederick Hopkins proved that vitamin A is destroyed by oxidation and strong heat.
In 1931, Swiss chemist Paul Karrer described the vitamin’s chemical structure. His research interest was intensified by competition with German biochemist Richard. The pigments of tomatoes and carrots were thoroughly investigated. Thanks to them it was discovered that β-carotene is a compound of vitamin A. The same year Harry Holmes and Ruth Corbet crystallized the vitamin. In 1937, Karrer was awarded the Nobel Prize in Chemistry for his research on carotenoids.
In 1946, van Dorp and Josef Ferdinand Arens published their study on the synthesis of vitamin A as an acid in the Nature scientific journal. In 1947, they reported the first complete synthesis of a vitamin A compound, converting the acid into alcohol. This discovery was not intended for commercial production, yet it had a significant impact in the scientific community.
Swiss chemist Otto Isler continued the work of his colleagues, developed a method of fat-soluble vitamin synthesis, and introduced the vitamins into production: 1938 – vitamin E, 1939 – vitamin K1, 1947 – vitamin A, 1960 – vitamin A2, and various aromatic substances. Later, biochemist George Wald discovered the vitamin A role in vision and won the Nobel Prize in Physiology or Medicine for it.
Just like any other vitamin, retinol is essential for human health. Without it you will lose your eyesight, your ability to resist infections, and have skin problems. We can get vitamin A from animal products such as liver, fish oil, egg yolk, milk, and butter. Plant analogs of vitamin A include carotenes found in carrots, peppers, green onions, lettuce, pumpkin, and tomatoes. However, you need to be careful with these products. The recommended daily intake of vitamin A for a person varies according to gender and age.
Read more about the discovery of vitamins in our article